CMOS Baseline Tracking and Cancellation Instrumentation for Nanoparticle-Coated Chemiresistors.

Area of Science:

• Nanotechnology
• Sensor Technology
• Integrated Circuits

Background:

• Thiolate-monolayer-protected gold nanoparticle (MPN) interfaces on chemiresistor (CR) sensors show potential for gas chromatography.
• MPN-coated CRs face challenges with wide baseline resistance ranges and drift, limiting their application.
• Biomedical and environmental analyses, including breath biomarker detection, require sensitive and stable sensor systems.

Purpose of the Study:

• To develop a novel readout circuit for MPN-coated CR sensors.
• To address and overcome the inherent limitations of baseline resistance and drift in MPN-coated CRs.
• To achieve high-resolution gas detection for advanced analytical applications.

Main Methods:

• Designed and implemented a 0.5-mum CMOS readout circuit operating at 5 V.
• Developed circuitry capable of canceling a wide range of baseline voltages (0.3–4.3 V) with high accuracy (4.2 mV).
• Integrated drift compensation mechanisms to track and correct variations up to 30 mV/min.

Main Results:

• Achieved a 57 ppm readout resolution for MPN-coated CR sensors.
• Demonstrated a response resolution of 74 μV.
• Successfully verified performance by measuring and effectively canceling drift in MPN-coated CRs.
• The circuit's design supports integration into on-chip sensor arrays.

Conclusions:

• The new readout circuit effectively overcomes baseline resistance and drift issues in MPN-coated CR sensors.
• The developed circuit enables high-resolution gas analysis for biomedical and environmental applications.
• The compact circuit design is suitable for on-chip integration, paving the way for advanced sensor arrays.